The critical moment for Sen. Ted Cruz and his allies came around 7 p.m. on Tuesday night.

The Texas Republican's suit was still crisp, despite more than four hours into what would become a rhetorical marathon of more than 21 hours on the Senate floor aimed at derailing Obamacare.

But until that point, the brunt of the speaking had been done by Cruz and his ally, Sen. Mike Lee, R-Utah. Without more help, Lee's aides weren't sure how long the effort could continue.

Then Sen. Marco Rubio, R-Florida, arrived. It was a sign that they'd get the bodies they needed for the long haul.

"When he showed up, we had a feeling that we could go until noon (the next day)," said Lee spokesman Brian Phillips.

Lee was on or near the floor all night. Sen. Rand Paul of Kentucky, who held the floor for 12 hours in March, jumped in. Even ideological opponent Sen. Dick Durbin, D-Illinois, shouldered some speaking time while trying to refute Cruz' points.

That gave Cruz some time for mental breaks even though he couldn't leave the floor to eat, use the restroom or do anything else.

For material, staff pulled together binders of articles, talking points and documents that could be used to fill time. And as social networks heated up, aides ferried in a stream of tweets for Cruz to read.

But to the big and less comfortable question: How did he manage physically?

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Good, pliable shoes, for a start. Cruz left his trademark Ostrich boots behind and told the chamber that he picked up some sneakers in preparation for the long hours of standing.

No food. Senate rules ban anyone from eating on the chamber floor. So that is easy.

Dehydration. CNN Senior Congressional Producer Ted Barrett asked Cruz how he stood for more than 21 hours without having to use the men's room.

"Drinking very little water," he replied.

That surely is part of it. But we do not know if anything else was involved, as has been the case in the past.

The Senate's marathon speech record-holder, the late Strom Thurmond of South Carolina, reportedly set up a bucket in the Senate cloakroom next to the chamber and used it while keeping one foot on the Senate floor, so as to retain his speaking position.

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Former Sen. Estes Kefauver of Tennessee used some kind of bag during his portion of a filibuster, according to an oral history from former parliamentarian Floyd Riddick. It did not end well.

"That's always a defining issue, how much stamina a person has," said Senate Historian Don Ritchie, who recorded the oral history with Riddick and says there is a tradition of senators using a contraption for bodily functions during speech-a-thons.

Cruz was on the Senate floor just 1 hour and 41 minutes short of a day.

"I don't know of any special thing he used," said Phillips. "And he didn't indicate there was anything."

Then he paused.

"That's one of those things that is so personal that there are only a couple of people who know. And they will probably take it to their graves."